It's talked about in a few places that hemalurgy is the most promising of the metallic arts, particularly because it can grant *anything* (or at least, anything written into the soul). Obviously, we can expect to see it show up in other places throughout the Cosmere, likely with some major effects.
Without spoiling anything directly (particularly the end of Bands of Mourning & Secret History), Hemalurgy seems like exactly the kind of brutal-but-efficient tool that a certain Mistborn will need to pursue their goals. I can easily see it becoming a sticking point between that character and other major actors in the greater Cosmere.
Obviously it's a pretty evil art in design, but I think the opportunities (both narrative and mechanical) it presents are fascinating.